The main north-south route through Bosnia was completed in 1966 in Tito’s Yugoslavia. It runs through Samac, Doboj, Sarajevo and Mostar, to Ploce on the Adriatic. However, it starts at the village of Vrpolje, which is on the main Zagreb – Belgrade line, but otherwise ‘in the middle of nowhere’. This illogical route was included in Pan-European Corridor Vc, only because nothing better was planned. No major work was done anyway, and these corridors are now under review.
The logical place for the north-south axis to start is Vinkovci, which is already a main railway junction. It would become more important with the high-speed lines (HSL) proposed here earlier. The Drava plain high-speed line, and the roughly parallel Sava valley high-speed line would converge at Vinkovci, and diverge again as high-speed routes to Belgrade, and to Novi Sad. The HSL Pécs – Osijek – Vinkovci would be the main north-south route into the region. Traffic form the Zagreb direction would however use the proposed Derventa cut-off line.
A new cut-off line from Vinkovci to Šamac would shorten the route between Vinkovci and Doboj, and create a much more logical junction with all other lines in the region.
There are no topographic obstacles to the line, although the area is low-lying. For about 15 km between Vinkovci and Cerna, the new line would parallel the existing branch line to Županja. The new line would also parallel the planned Sava – Danube canal (it has been planned since 1792).
Šamac is located at the confluence of the Bosna and Sava rivers. The original Austro-Hungarian line from Vrpolje opened in 1878: it terminated on the opposite bank of the Sava. The river was the border with Bosnia, which had just been occupied by Austria-Hungary. Only after the Second World War, was Šamac connected to Doboj and Sarajevo, replacing the earlier narrow-gauge route from Slavonski Brod. The line Šamac – Doboj follows the Bosna river: that is a logical route, but the connection to Vrpolje is not.
Click to enlarge: The original railway geography, from an Austro-Hungarian military map of around 1910, Šamac branch highlighted in blue…
Šamac is geographically in Bosnia, and is sometimes known as Bosanski Šamac. However, it is part of the Republika Srpska, which calls it simply Šamac. The settlement across the river, on the Croatian side, is known as Slavonski Šamac. The existing road/rail bridge (single-track) is sufficient for the limited traffic. A new line would need a double-track bridge, with a better approach curve.
At Vinkovci, the new cutoff line would approach from the west, alongside the local line from Županja (Croatian line L210). It would join the main line from Zagreb near the station. The low density in Vinkovci would allow a surface line with overbridges.
The alignment between Šamac and Vinkovci would be determined by local conditions. The planned canal is also intended for drainage, and runs through the lowest terrain, following smaller rivers. The new rail line can not entirely avoid these former marshes, which are clearly shown on the 1910 map. The best option is probably an alignment just west of Babina Greda, crossing both the canal and the motorway. It would then turn north-east, following the canal toward Cerna: this section would be on viaduct.
The new line is intended for long-distance traffic, and would have no intermediate stations. The local line to Županja would be left much as it is, with a third track alongside the new line in Vinkovci itself. The new line would be about 38-40 km long, from the Sava bridge to Vinkovci station. That is about 15 km shorter than the existing route via Vrpolje, and with a new alignment, the journey time will be much shorter.